On-Board Charging Circuit for Shared AC/DC Input Isolation

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Solution Overview

Problem

Existing on-board charging systems require separate external input terminals for AC and DC power inputs, leading to high costs and limited adaptability, especially when dealing with charging stations that integrate both types, and pose a risk of damage from high-voltage DC inputs.

Innovation Solution

An on-board charging circuit with a switching module that can adapt to different power inputs, including AC and DC, using a pre-charging module with adjustable resistance and a rectifier module to ensure reliable electrical isolation and efficient voltage conversion, allowing a single set of terminals to handle multiple input types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate external input terminals are used for AC and DC power inputs, then connection safety is improved, but device complexity and cost increase

Engineering Contradiction:
Improveconnection safetyVSAvoidnumber of external input terminals
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single external input terminal that can accept both AC and DC power inputs. The terminal is equipped with detection circuitry that automatically identifies the input type and switches to the appropriate charging mode, eliminating the need for separate AC and DC terminals while maintaining connection safety through intelligent discrimination.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces an intermediary detection and control module between the external input terminal and the charging circuit. This intermediary detects the input power type (AC or DC) and controls the switching between different charging modes, thereby protecting the charging circuit from damage while enabling a single terminal to serve multiple purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a single external input terminal is used for both AC and DC power inputs, then adaptability is improved, but risk of component damage increases

Engineering Contradiction:
Improveadaptability to different power inputsVSAvoidrisk of component damage
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by detecting the external power input type (AC or DC) before the charging process begins. The detection circuitry identifies the input type and pre-configures the charging circuit accordingly, ensuring that the appropriate charging mode is activated before power is supplied, thereby preventing component damage from mismatched charging modes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback through a detection circuit that continuously monitors the external power input and provides feedback to the control module. Based on this feedback, the control module automatically switches between AC charging mode and DC charging mode, ensuring that the charging circuit operates in the correct mode and preventing damage from improper charging configurations.

Inventive Principle:
Principle #23Feedback

3Power

If high-voltage DC power input is accepted, then charging power is improved, but electrical isolation requirements increase

Engineering Contradiction:
Improvecharging powerVSAvoidelectrical isolation
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent introduces an intermediary detection and control module that mediates between the high-voltage DC input and the charging circuit. This intermediary detects DC input and activates electrical isolation mechanisms, thereby enabling high-power DC charging while maintaining safety through proper isolation of the charging circuit from the high-voltage source.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables cost-effective adaptability to various power inputs while ensuring reliable electrical isolation, reducing the risk of component damage and enhancing safety and efficiency in charging electric vehicles.

Implementation Method 1

the pre-charging module has a larger charging resistance in a pre-charging state than in a conventional charging state

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

a rectifier module, for receiving an external power input, and rectifying the external power input to charge the energy storage module

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP4671036A1On-board charging circuit, on-board charging device, on-board charging system and vehicle
Publication Date: 2025.12.31 VALEO ELECTRIFICATION
  • EP4671036A1 patent drawingFigure 1~2
  • EP4671036A1 patent drawingFigure 3~4
  • EP4671036A1 patent drawing

AI summary

The present disclosure relates to an on-board charging circuit, comprising: an energy storage module, for supplying a DC bus voltage; a rectifier module, for receiving an external power input, and rectifying the external power input to charge the energy storage module; a switching module, for controlling the supply of the external power input to the rectifier module; and a pre-charging module, connected in series with the energy storage module, and used for controlling a charging current to the energy storage module, wherein the pre-charging module has a larger charging resistance in a pre-charging state than in a conventional charging state. The present disclosure further relates to an on-board charging device, an on-board charging system and a vehicle.